Convert betting odds to probability and find value bets
Implied probability reveals what the sportsbook believes is the true chance of an outcome occurring, expressed as a percentage derived from betting odds. When you convert odds like -110, +150, or 2.50 into probability percentages, you gain insight into how the bookmaker has priced the market—and more importantly, where they may have made pricing errors. This calculator instantly converts American, decimal, and fractional odds formats into implied probabilities, helping you identify +EV (positive expected value) opportunities across NFL, NBA, NHL, MLB, NCAAF, and soccer betting.
Finding value in sports betting requires comparing the bookmaker's implied probability against your own probability assessment. If you believe an NFL team has a 60% chance to cover the spread, but the odds imply only a 52% probability, you've found a value bet with positive expected value. Professional bettors live and die by this edge-finding process—it's the mathematical foundation of long-term profitability. Our tool eliminates conversion errors and allows rapid comparison across multiple odds to spot discrepancies between books or identify mispriced markets.
Understanding the vig (vigorish or juice) embedded in odds is equally critical. Sportsbooks build their profit margin into odds, making the sum of implied probabilities exceed 100%. By calculating true probability and accounting for the vig, sharp bettors separate genuine edges from bookmaker manipulation. Use this calculator alongside statistical models, injury reports, and BetLegend's expert analysis to validate your handicapping and ensure you're only placing bets with demonstrable mathematical advantages over the closing line.
American (+150), Decimal (2.50), or Fractional (3/2)
Based on your research and analysis, what do YOU think the actual probability is?
Enter your true probability estimate to see if this is a value bet
Finding value bets is the foundation of profitable sports betting. This calculator helps you compare the bookmaker's implied probability against your own assessment to identify betting opportunities with positive expected value.
The key is being honest and accurate with your own probability estimates. Over hundreds of bets, your edge comes from consistently identifying these discrepancies.
Implied probability is the likelihood of an outcome based on the betting odds offered by a sportsbook. It represents the bookmaker's assessment of how likely an event is to occur, with their profit margin (vig/juice) built in.
Understanding implied probability is essential because it allows you to:
When your calculated true probability exceeds the implied probability, you have an edge
Convert all odds to probabilities to quickly see which book offers the best value
Determine whether a bet has positive or negative expected value over the long term
Make informed decisions about bet sizing based on your perceived edge
The break-even percentage is how often a bet must win for you to break even. This is essentially the same as implied probability. If a bet has 52.38% implied probability (like standard -110 odds), you need to win more than 52.38% of those bets to be profitable.
Professional bettors don't just bet on who they think will win - they bet when the odds offer value. Here's the step-by-step process:
Use this calculator to convert the bookmaker's odds into an implied probability percentage. This tells you what the sportsbook thinks the chances are.
Based on your research, analysis, and expertise, determine what YOU believe the actual probability is. This is where handicapping comes in:
If your true probability is higher than the implied probability, you've found value:
Even when you find value, bet sizing matters. Use the Kelly Criterion to determine the optimal bet size based on your edge and bankroll.
When you add up the implied probabilities of all possible outcomes in a market, they total more than 100%. The excess is the bookmaker's profit margin.
If you consistently bet at better odds than the closing line, you're likely a winning bettor. Track whether your bets beat the closing implied probability.
Some markets are more efficient than others. NFL point spreads are highly efficient (hard to find value). NBA player props and smaller leagues often have more opportunities.
Your true probability estimates won't always be perfect. What matters is being correct on average over hundreds of bets. Don't get discouraged by short-term variance.
Be Conservative With Your Estimates: It's easy to talk yourself into thinking a bet has more value than it does. Stay objective and be honest about uncertainty.
Shop for the Best Lines: A bet might not have value at -110 but could have value at +100. Having accounts at multiple sportsbooks is crucial.
Track Your Results: Keep detailed records of your bets and your pre-game probability estimates. This data will show whether your handicapping is actually sharp.
Specialize: You don't need to bet everything. Find a sport, league, or bet type where you have genuine expertise and focus there.
Avoid Public Bias: When the public hammers one side, bookmakers adjust the line. Sometimes the less popular side offers better value.
Don't Chase Losses: Just because you lost doesn't mean your probability estimate was wrong. Variance happens. Stick to your process.
Consider the Juice: A bet at -105 has more value than the same bet at -110, even if the spread is identical. Shop for reduced juice sportsbooks.
Join BetLegend for data-driven picks with verified results
See Our Verified Record 🎯